*2.2. Study of the Structure, Elemental Composition, and Tribological Properties*

The study of the samples' structure was carried out on a scanning electron microscope VEGA 3 LMH manufactured by Tescan (Brno, Czech Republic). This instrument was equipped with an Oxford Instruments INCA Energy energy-dispersive X-ray spectroscopy (EDX) system.

Two spectroscopic techniques were used for an analysis and study of the elemental composition of the near-surface layer of the samples of the cutting tool and the workpiece being processed:


The evaluation of the coefficient of friction (COF) of the surface layer of the samples was carried out on a TNT tribometer manufactured by Anton Paar TriTec SA (CorcellesCormondrèche, Switzerland) according to a pin-on-disc method (ASTM G99 17 standard [81]) under the following test conditions (Table 2).

**Table 2.** Test conditions for evaluation of the friction coefficient (a pin-on-disc method).


Samples were made from various types of tool materials such as discs with a diameter of 19 mm and a height of 8 mm for tribological tests. The same samples were used to evaluate the resistance of the surface layer of the samples to abrasion by testing on a CALOTEST device manufactured by CSM Instruments (Needham Heights, MA, USA) under the conditions of force acting on the sample of a rotating sphere when a water-based abrasive slurry was fed into the contact zone. Optical analysis of the geometric dimensions of the wear hole and its measurement on a Dektak XT stylus profilometer manufactured by Bruker AXS GmbH (Karlsruhe, Germany) to quantify the intensity of samples' wear was carried out.
